Flamespeaker's Will is a common Enchantment — Aura card from Journey into Nyx (JOU), collector number 95. Current market price: $0.16 (foil $0.20), TCGplayer market prices via Scryfall.
Enchant creature you control Enchanted creature gets +1/+1. Whenever enchanted creature deals combat damage to a player, you may sacrifice this Aura. If you do, destroy target artifact.